UV wavelength lighting has a wide variety of applications including the curing of inks, coatings, sealants, and adhesives. Curing with UV LED lighting is becoming increasingly popular as an alternative to curing with conventional UV mercury lamps because of its higher energy efficiency, concentrated power output, longer operating lifetime, lower heat generation, and environmental friendliness. (LED lighting contains no mercury and doesn't produce ozone). Curing with UV lighting is generally done with some form of curing unit; the main components of a UV LED curing unit include UV LED modules and a cooling system for heat removal.
It is known that prior UV LED curing units can comprise one or more LED array modules mounted on one or more heat sinks, optical systems, e.g., reflectors and lenses, and a unit enclosure. The LED array modules contain arrays of universal LED packages that need to be protected, or further focused to achieve the desired intensity for the curing application through secondary lenses and reflectors. Reflectors may be integrated with the LED array modules. Secondary lenses are necessary with these conventional systems. Because of this, the airgap between the primary lens and the secondary lens, reduces the UV energy output efficiency and produce more heat. In addition, an enclosure for the curing unit is necessary to hold the reflector and the secondary lenses. Such heat sinks may use thermally-dissipating fins, or chambers formed by adjacent plates that allows a cooling liquid (or air) to pass through for removal of heat. Versions also use multiple micro channels formed by a stack of plates that allow liquid or air to pass through. Conventionally, heat sinks have been housed within the curing unit, or within a separate enclosure.
It is also known that prior UV LED curing units may comprise: an LED assembly with multiple large chips mounted with insulating resin (barriers to heat) on a conductive plate, then on a heat sink that includes or comprises a water rail with channels, optical systems such as a reflector and lens, end caps to form a fluidic circuit in the water rail, end caps with connectors, a separate enclosure for the heat sink, reflector and LED assembly. Reflectors and the lenses for the curing unit are not integrated with the LED assembly with these conventional systems.
The above LED array modules/assemblies are known to comprise LED chips mounted on either Metal Core Printed Circuit Board (hereafter MCPCB), ceramic, or silicon. Mounting chips on MCPCB generally creates multiple additional insulating layers that act as heat barriers. In these arrangements, ceramic itself is the insulating layer. Silicon, when used, has superior heat dissipation than exists with some other methods, but still introduces an extra insulating layer to the system.